JPH03213771A - Variable speed control device for automatic transmission - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application) The present invention relates to a shift control device for an automatic transmission, and more particularly to a shift control device for an automatic transmission that improves start-up performance from cornering.

(Prior art) - When driving on a road that goes from a straight road to a turning road (hereinafter also referred to as a corner) and then back to a straight road again, the driver loosens the throttle/nottle pedal (specifically, (take your foot off the pedal), depress the brake pedal with that foot if necessary to reduce the vehicle speed to a speed suitable for cornering, then shift to cornering while operating the steering wheel, and then re-start near the exit of the corner. It performs a series of actions such as depressing the throttle pedal and accelerating again.

By the way, during such cornering, in a vehicle equipped with a manual transmission, it is desirable to perform a downshift operation at the same time as deceleration. This is because if you switch to a lower gear in advance, your re-acceleration performance will be much improved and you will be able to get out of a corner more quickly.

On the other hand, in vehicles with automatic transmissions, unless you actively switch from D (drive) range to ■ range or I range, you cannot downshift in advance, compared to vehicles with manual transmissions. Corner start-up tends to be slow. In addition, upshifts were sometimes performed in response to depressing the throttle pedal back when entering a corner, resulting in insufficient performance when starting from a corner. This is because the automatic transmission's shift control automatically selects an appropriate gear according to the relationship between the degree of depression of the throttle pedal (throttle opening) and the vehicle speed. If the speed exceeds the shift-up point on the shift diagram, select the selected gear (for example, 3rd gear) when driving straight ahead.
This is because the gear position is automatically shifted to the higher gear position (4th gear).

In order to solve these disadvantages peculiar to automatic transmissions,
A control device for an automatic transmission is equipped with a kickdown function that forcibly selects a lower gear in response to depression of a throttle pedal. However, in order to activate this function, a special operation is required in which the throttle pedal is firmly pressed all the way to the floor. This function can only be performed by drivers who like to accelerate, so it cannot be said to be an effective function for the majority of drivers who gradually press the pedal more and more to accelerate near the exit of a corner.

In view of these various points, for example, Japanese Patent Application Laid-Open No. 59-20
"Shift control device for automatic transmission" described in Publication No. 0840
(hereinafter referred to as conventional device), cornering is performed when the steering angle of the steering wheel is above a predetermined value (to put it simply, the steering wheel is turned in a J! manner, and the throttle opening is fully closed). It is determined whether the vehicle is running, and at the time of this determination, downshift control is performed to the nearest lower gear (for example, from 3rd gear to 2nd gear).

According to this, it is possible to switch to a lower gear in advance before starting acceleration near the exit of a corner, and without relying on the kink down function (when accelerating again, a large driving force is immediately applied to the drive wheels to improve acceleration performance). It is possible to improve both the acceleration response and the acceleration response.

(Problem to be Solved by the Invention) However, such conventional devices are configured to determine cornering and perform downshift control without exception when this determination is made (with the exception of when overswing is predicted). , there is an inherent problem that the driving force during re-acceleration may be excessive compared to the road surface conditions, etc., which may actually increase the slippage of the driving wheels (hereinafter referred to as driving slip), making the driving condition unstable. It was something.

In other words, in general, to exit a corner quickly, (
Two points are important: 1) setting the acceleration start point at the corner clipping point, and (n) applying an appropriate amount of driving force to the drive wheels to the extent that no drive slip occurs. For example, when driving on a circuit, proper line alignment and smooth throttle pedal operation are required.
This must be avoided at all costs, as it increases drive slip and slows down the corner start-up speed, which not only leads to time loss but also causes spin.

In addition, the appropriate driving force mentioned in (n) above is determined not only by the degree of depression of the throttle but also by the tire performance (so-called grip force).
It is also related to road surface μ, gear ratio (and therefore gear stage), etc. In other words, drive wheels using tires with low grip force react sensitively to even the slightest increase in drive force and promote drive slip, which not only affects the road surface coefficient but also reduces the gear shift on the lower side. Since a gear position (for example, 2nd gear) has a power characteristic in which the driving force increases rapidly compared to an upper gear position (eg, 3rd gear), drive slip is similarly promoted.

Therefore, if the conventional device simply determines cornering and performs downshift control, the slight drive slip that occurs may be exacerbated depending on the degree to which the throttle pedal is pressed and the road surface conditions at that time. ,
On the contrary, there is a problem in that the driving condition becomes unstable.

(Purpose of the Invention) The present invention has been made in view of the problems of the conventional device as described above. By prohibiting down control, the purpose is to avoid a decrease in driving stability.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a steering state detection means IO for detecting the steering state of a steering wheel, and an engine load. a load detecting means 11 for detecting the steering state, a determining means 12 for determining the re-acceleration state during cornering based on the signal from the steering state detecting means 10 and the signal from the load state detecting means 11; A signal generating means 13 that generates a downshift signal instructing a change to a lower gear, a slip amount detecting means 14 that detects the slip amount of the driving wheels, and a slip amount detecting means 14 that detects the slip amount of the driving wheels, and a slip amount detecting means 14 that detects the amount of slip of the driving wheels. prohibition means 15 for prohibiting generation of the shift down signal when the shift down signal is exceeded;
It is characterized by the following.

(Function) In the present invention, when the amount of slip occurring in the drive wheels exceeds a predetermined reference slip amount during re-acceleration during cornering, generation of a downshift signal instructing a change to a lower gear is prohibited. Ru.

Therefore, drive slip during re-acceleration is not promoted, a reduction in running stability is avoided, and the safety of the vehicle is ensured.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 2.3 is a diagram showing an embodiment of a speed change control device for an automatic transmission according to the present invention.

First, the configuration will be explained. In Figure 2, 20 is the front wheel;
21 is the rear wheel. Here, assuming a front-wheel drive vehicle, the front wheels 20 are assumed to be the driving wheels. 22 is a steering wheel that steers the front wheels 20 via a rack and pinion gear mechanism 23;
25 is a steering angle sensor serving as a steering state detection means for detecting the steering angle θ of the steering handle 22; 25 is an automatic transmission that increases or decreases engine torque by changing a plurality of gears according to a predetermined gear shift signal SS, and transmits the increased or decreased engine torque to the front wheels 20; , 26 is a throttle sensor as a load state detection means for detecting the throttle opening (corresponding to the engine load) TVO that changes in response to the degree of depression of the throttle pedal (as shown); 27
- 30 are wheel speed sensors that detect the respective speeds of the left and right front wheels 20 and the left and right rear wheels 21;
31 is a controller including a microcomputer and the like.

The controller 31 is a determining means, a signal generating means, and a pickpocket 7.
It has the functions of a lid detection means and a prohibition means, and executes speed change control of the automatic transmission according to a predetermined program.

Here, the speed change control of this embodiment is performed by the throttle sensor 26.
TVO and vehicle speed VR (VR is, for example, rear wheel speed,
■. In addition to the normal shift control operation of determining one gear position based on the average value of
The re-acceleration state during cornering is determined based on θ from 4 and TVO from the throttle sensor 26, and at the time of determination, the state of re-acceleration during cornering is determined. a shift down signal (the above-mentioned shift signal SS
(also used) However, ■VFL, ■□
, ■1, ■□The slip amount β of the driving wheel 20 is obtained from ■□.
If the amount of slip exceeds a predetermined reference slip amount βIEF, generation of the downshift signal is prohibited, in other words, downshift control is not performed.

Next, the effect will be explained.

FIG. 3 is a diagram showing the main part of the speed change control program stored in the controller 31, and shows a flowchart part specific to this embodiment.

In this flowchart, first, when the steering angle θ from the steering angle sensor 24 exceeds a predetermined angle, cornering is determined (step 40), and then the throttle opening T\
10 exceeds a predetermined opening degree (at least an opening degree smaller than the kick-down determination opening degree), re-acceleration is determined from depression of the throttle pedal (step 41). That is,
If only step 40 is a YES command, it is determined that the cornering is in progress, while steps 40 and 41 are both YES.
If it is an ES command, the re-acceleration state near the exit of the corner is determined.

Then, when determining the re-acceleration state, the slip ratio of the driving wheels (here, the front wheels 20) is calculated based on each wheel speed, for example, according to the following equation 1 (step 42).

The slip ratio has a value of 1 when the wheel speed difference between the front wheels 20 and the rear wheels 21 is zero, but when the front wheels 20 spin and the wheel speeds ■FL, ■□ increase, the slip ratio increases in proportion to the amount of increase. Since an increasing value is obtained, the slip ratio represents the slip (driving slip) amount β of the front wheels 20.

Again, in the flowchart, it is determined whether β obtained by the above calculation exceeds the predetermined reference slip amount βREF (step 43), and if it does not (YES command), the current gear is switched to the immediately lower gear. A downshift signal is generated to instruct (step 44). If it exceeds the limit (NO instruction), step 44 is passed, the current process is ended, and the process from step 40 is repeated.

That is, if the driving slip amount β at the time of starting up from cornering (in other words, at the time of re-acceleration) is large enough to exceed a predetermined reference slip amount βIEF, downshift control is prohibited.

Therefore, according to this embodiment, when depressing the throttle pedal near the exit of a corner and transitioning to re-acceleration, if no drive slip occurs, downshift control can be executed to improve acceleration performance; If so, it is possible to inhibit downshift control and improve driving stability. As a result, it is possible to avoid spins and the like and improve the running stability of the vehicle.

In the conventional device, shifting and down are performed before re-acceleration. In addition, a normal kickdown is performed by depressing the throttle 7 and tor pedals to the floor. Although conventional devices have excellent acceleration and responsiveness, their running stability is questionable, and the kickdown system also has the drawback of being difficult to use for ordinary drivers.

In contrast, in this embodiment, the state of re-acceleration from cornering is determined by a slight depression of the throttle pedal, and downshifting is performed only when the amount of drive slip detected at the time of re-acceleration determination is small. Therefore, it is possible to achieve both acceleration and running stability without requiring special pedal operations like kickdown.

Of course, it is undeniable that the responsiveness of the driver is lower than that of the conventional device that downshifts in advance, but since it solves the extremely important problem of improving driving stability, this embodiment Furthermore, we can provide useful technology.

(Effects) According to the present invention, it is possible to place emphasis on the driving stability of the vehicle, and to prohibit downshift control when the driving wheel slip is large even when starting from a corner, thereby avoiding a decrease in driving stability. can.

[Brief explanation of drawings]

Fig. 1 is a conceptual block diagram of the present invention, Figs. 2 and 3 are diagrams showing an embodiment of a shift control device for an automatic transmission according to the present invention, Fig. 2 is a system block diagram thereof, and Fig. 3 is a diagram showing an embodiment of the shift control device for an automatic transmission according to the present invention. is a flowchart of the main part of the speed change control program. 10... Steering state detection means, 11... Load state detection means, 12... Judgment means, 13... Signal generation means, 14... ...Slip amount detection means, 15...
・Prohibiting means, 24...- Rudder angle sensor (steering state detection means), 26
... Throttle sensor (load state detection means), 31 ... Controller (judgment means, signal generation means, slip amount detection means, inhibition means). Fig. 1 Fig. 24; Rudder angle sensor (steering state detection means) 26: Throttle sensor (load state! l314: output means) 31: Controller (judgment means, signal generation means, spring detection means, inhibition means )

Claims (1)

[Claims] Steering state detection means (10) for detecting the steering state of the steering wheel; and load detection means (10) for detecting the engine load.
1), a determining means (12) for determining a re-acceleration state during cornering based on a signal from the steering state detecting means (10) and a signal from the load state detecting means (11); Signal generating means (13) that generates a downshift signal to instruct switching to the immediately lower gear; and slip amount detecting means (14) that detects the amount of slip of the driving wheels.
), and prohibiting means (15) for prohibiting generation of the downshift signal when the detected slip amount exceeds a predetermined reference slip amount. Device.